Diffuse X-ray scattering in WO<sub>3</sub>

Locherer, K. R.; Chrosch, J.; Salje, Ekhard K. H.

doi:10.1080/01411599808219188

Cited by 41 publications

(36 citation statements)

References 21 publications

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“…Diffuse x-ray scattering can also be used to investigate the structure of domains and domain walls in densely twinned ferroelastic crystals (Bruce, 1981;Andrews and Cowley, 1986;Locherer, Chrosch, and Salje, 1998). The scattering is characterized by strong, well-defined Bragg peaks, with a diffuse streak between these arising from the domain walls (see Fig.…”

Section: X-ray Diffraction and Imagingmentioning

confidence: 99%

“…The streak typically is several orders of magnitude lower in intensity. Comparison with an analytical model for the scattering allows one to extract the effective domain wall width on the unit-cell level (Locherer, Chrosch, and Salje, 1998). Critical fluctuations and domain walls of, for example, KH 2 PO 4 (KDP) and KD 2 PO 4 (DKDP) were investigated (Andrews and Cowley, 1986).…”

Section: X-ray Diffraction and Imagingmentioning

confidence: 99%

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Domain wall nanoelectronics

et al. 2012

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Domains in ferroelectrics were considered to be well understood by the middle of the last century: They were generally rectilinear, and their walls were Ising-like. Their simplicity stood in stark contrast to the more complex Bloch walls or Néel walls in magnets. Only within the past decade and with the introduction of atomic-resolution studies via transmission electron microscopy, electron holography, and atomic force microscopy with polarization sensitivity has their real complexity been revealed. Additional phenomena appear in recent studies, especially of magnetoelectric materials, where functional properties inside domain walls are being directly measured. In this paper these studies are reviewed, focusing attention on ferroelectrics and multiferroics but making comparisons where possible with magnetic domains and domain walls. An important part of this review will concern device applications, with the spotlight on a new paradigm of ferroic devices where the domain walls, rather than the domains, are the active element. Here magnetic wall microelectronics is already in full swing, owing largely to the work of Cowburn and of Parkin and their colleagues. These devices exploit the high domain wall mobilities in magnets and their resulting high velocities, which can be supersonic, as shown by Kreines' and co-workers 30 years ago. By comparison, nanoelectronic devices employing ferroelectric domain walls often have slower domain wall speeds, but may exploit their smaller size as well as their different functional properties. These include domain wall conductivity (metallic or even superconducting in bulk insulating or semiconducting oxides) and the fact that domain walls can be ferromagnetic while the surrounding domains are not.

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Section: X-ray Diffraction and Imagingmentioning

confidence: 99%

Section: X-ray Diffraction and Imagingmentioning

confidence: 99%

Domain wall nanoelectronics

et al. 2012

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“…X-ray diffraction methods have proved to be a powerful tool to study twinning microstructures and their associated domain boundaries, provided care is taken to optimize the collection and processing of the diffraction signal (Chrosch & Salje, 1994Wruck et al, 1994;Locherer et al, 1998). Reciprocal-space studies (that is, diffraction rather than microscopy) are preferable since, although each individual twin boundary occupies a tiny volume (and hence will give a very small experimental signal), diffraction experiments allow for the superposition of the signals from a large number of essentially identical twin walls.…”

Section: Theoretical Basismentioning

confidence: 99%

Ferroelastic phase transitions: structure and microstructure

Salje

Hayward

Lee

2004

Acta Crystallogr A Found Crystallogr

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Landau-type theories describe the observed behaviour of phase transitions in ferroelastic and co-elastic minerals and materials with a high degree of accuracy. In this review, the derivation of the Landau potential G = 1 2 A S [coth( S /T) À coth( S /T C )]Q 2 + 1 4 BQ 4 + F F F is derived as a solution of the general 0 4 model. The coupling between the order parameter and spontaneous strain of a phase transition brings the behaviour of many phase transitions to the mean-®eld limit, even when the atomistic mechanism of the transition is spin-like. Strain coupling is also a common mechanism for the coupling between multiple order parameters in a single system. As well as changes on the crystal structure scale, phase transitions modify the microstructure of materials, leading to anomalous mesoscopic features at domain boundaries. The mesostructure of a domain wall is studied experimentally using X-ray diffraction, and interpreted theoretically using Ginzburg±Landau theory. One important consequence of twin mesostructures is their modi®ed transport properties relative to the bulk. Domain wall motion also provides a mechanism for superelastic behaviour in ferroelastics. At surfaces, the relaxations that occur can be described in terms of order parameters and Landau theory. This leads to an exponential pro®le of surface relaxations. This in turn leads to an exponential interaction energy between surfaces, which can, if large enough, destabilize symmetrical morphologies in favour of a platelet morphology. Surface relaxations may also affect the behaviour of twin walls as they intersect surfaces, since the surface relaxation may lead to an incompatibility of the two domains at the surface, generating large strains at the relaxation. Landau theory may also be extended to describe the kinetics of phase transitions. Time-dependent Landau theory may be used to describe the kinetics of order±disorder phase transitions in which the order parameter is homogeneous. However, the time-dependent Landau theory equations also have microstructural solutions, explaining the formation of microstructures such as tweed.

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“…There are few experimental observations which confirm these results; probably the most extensive study is by Chrosch and Salje [77] who measured the wall thickness in LaAlO 3 as a function of temperature over a very large temperature interval [78][79][80][81][82][83][84][85][86][87].…”

Section: Structural Modifications Of Twin Walls: the Role Of The Secomentioning

confidence: 67%